We propose to study the relationship between the defining symptoms of two eating disorders, anorexia nervosa and bulimia, and psychiatric impairment in adolescents. The cooperation of all the secondary schools in a single county enables us to study this relationship in a geographically circumscribed, clinically unreferred population of approximately 5,500 adolescents, ages 14-18 years. A two-stage design will be employed in which screening by self-report questionnaire is followed by structured diagnostic interviews. Adolescents will be selected for interview based upon a two factors (body mass and eating attitudes) stratified random sample design. Adolescents who are statistically abnormal on these two factors will be over sampled. The first and principal aim of this study is to determine the degree to which the defining symptoms of the two eating disorders (e.g., dieting and binge-eating) are associated with both nonspecific psychiatric impairment and specific psychiatric diagnoses in the general population. This information will assist clinicians in assigning relative diagnostic weight to presenting symptoms and to target treatment efforts. The second aim is to determine prevalence rates for the eating disorders by age, sex, and SES groupings of adolescents in a geographically defined area; this may provide clues as to the etiology and pathogenesis of these disorders. The third aime is to determine the screening properties of the various screening scales used in the questionnaire; this may help refine tools for screening for potentially handicapping conditions. The fourth aim is to establish norms for adolescents on measures developed and used in clinical populations; this will enrich the interpretation of clinical data.